One is a Trek concept store. The other stocks Specialized and Giant. The third one seems to stock everything under the sun, yet only "online". Their brick 'n mortar store must be a front for something!They are sounding like 'concept' stores. Trek stores seem generally to be Trek/Bontrager only. Spesh are similar here, to a lesser extent, and do stock other brands. The Giant stores I know of stock more than just giant, but attempting to get non 27.5/29 quality gear is impossible.
Our local Trek store is bonza generally, they have previously had the tubes I needed......most likely a generic tube in a fancy bontrager box, mind.